Aug. 9, 2010 -- Men and women who are very large around the middle are at much greater risk of dying from any cause than people with thinner waists, a new study says.

Eric J. Jacobs, PhD, and colleagues at the Atlanta-based American Cancer Society, examined associations between waist circumference and the risk of death in 48,500 men and 56,343 women aged 50 and older.

They found that people with very large waists -- 47 inches or more for men and 42 inches and more in women -- were about twice as likely to die, compared to thinner people, and not just from weight-related problems.

All participants had completed a mailed questionnaire about demographic, medical, and behavior factors and provided information about weight and waist circumference during the 1990s. Over a nine-year follow-up period, 9,315 men and 5,332 women died.

A larger waist was associated with a higher risk of death across all measures of BMI, or body mass index, including people of normal weight and people who were overweight and obese.

A somewhat surprising finding was that among women, the risk association between waist size and death was strongest for those with a normal BMI. Researchers say the reason is unclear and that more study is needed.

Reshaping Obesity Guidelines

The study findings could affect the development of future guidelines on obesity.

"Currently available clinical guidelines from the National Institutes of Health are based on evidence from the 1990s," the researchers say. "These guidelines recommend that waist circumference be used to identify increased disease risk only among individuals in the overweight and obese categories of BMI."

NIH guidelines recommend weight loss goals for all patients with a BMI of 30 or greater. BMI is a ratio of a person's weight to their height to determine degree of body fat. A person with a BMI of less than 18.5 is considered underweight, 25-29.9 is overweight, and 30-39.9 means obese. A BMI of 40 or more means dangerously obese.

The study authors say the NIH guidelines do not specifically recommend weight loss goals for abdominally obese patients who are in the normal or overweight categories unless they also have two or more cardiovascular risk factors or a desire to lose weight.

Large waist circumference has been shown to be associated with higher circulating levels of inflammatory markers, insulin resistance, type 2 diabetes, and coronary heart disease. More than 50% of men and 70% of women in the United States exceed waist circumference thresholds.

The scientists conclude that their study provides evidence that a larger waist circumference may have important adverse health effects, even among people with a BMI lower than 30. They conclude that regardless of weight, people should avoid allowing themselves to become too big around the middle.

The study is published in the Aug. 9 issue of the Archives of Internal Medicine.